/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */
package javax.swing.text;

import java.io.Serializable;

/**
 * This class encapsulates a single tab stop (basically as tab stops
 * are thought of by RTF). A tab stop is at a specified distance from the
 * left margin, aligns text in a specified way, and has a specified leader.
 * TabStops are immutable, and usually contained in TabSets.
 * <p>
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future Swing releases. The current serialization support is
 * appropriate for short term storage or RMI between applications running
 * the same version of Swing.  As of 1.4, support for long term storage
 * of all JavaBeans&trade;
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 */
public class TabStop implements Serializable {

  /**
   * Character following tab is positioned at location.
   */
  public static final int ALIGN_LEFT = 0;
  /**
   * Characters following tab are positioned such that all following
   * characters up to next tab/newline end at location.
   */
  public static final int ALIGN_RIGHT = 1;
  /**
   * Characters following tab are positioned such that all following
   * characters up to next tab/newline are centered around the tabs
   * location.
   */
  public static final int ALIGN_CENTER = 2;
  /**
   * Characters following tab are aligned such that next
   * decimal/tab/newline is at the tab location, very similar to
   * RIGHT_TAB, just includes decimal as additional character to look for.
   */
  public static final int ALIGN_DECIMAL = 4;
  public static final int ALIGN_BAR = 5;

    /* Bar tabs (whatever they are) are actually a separate kind of tab
       in the RTF spec. However, being a bar tab and having alignment
       properties are mutually exclusive, so the reader treats barness
       as being a kind of alignment. */

  public static final int LEAD_NONE = 0;
  public static final int LEAD_DOTS = 1;
  public static final int LEAD_HYPHENS = 2;
  public static final int LEAD_UNDERLINE = 3;
  public static final int LEAD_THICKLINE = 4;
  public static final int LEAD_EQUALS = 5;

  /**
   * Tab type.
   */
  private int alignment;
  /**
   * Location, from the left margin, that tab is at.
   */
  private float position;
  private int leader;

  /**
   * Creates a tab at position <code>pos</code> with a default alignment
   * and default leader.
   */
  public TabStop(float pos) {
    this(pos, ALIGN_LEFT, LEAD_NONE);
  }

  /**
   * Creates a tab with the specified position <code>pos</code>,
   * alignment <code>align</code> and leader <code>leader</code>.
   */
  public TabStop(float pos, int align, int leader) {
    alignment = align;
    this.leader = leader;
    position = pos;
  }

  /**
   * Returns the position, as a float, of the tab.
   *
   * @return the position of the tab
   */
  public float getPosition() {
    return position;
  }

  /**
   * Returns the alignment, as an integer, of the tab.
   *
   * @return the alignment of the tab
   */
  public int getAlignment() {
    return alignment;
  }

  /**
   * Returns the leader of the tab.
   *
   * @return the leader of the tab
   */
  public int getLeader() {
    return leader;
  }

  /**
   * Returns true if the tabs are equal.
   *
   * @return true if the tabs are equal, otherwise false
   */
  public boolean equals(Object other) {
    if (other == this) {
      return true;
    }
    if (other instanceof TabStop) {
      TabStop o = (TabStop) other;
      return ((alignment == o.alignment) &&
          (leader == o.leader) &&
          (position == o.position));  /* TODO: epsilon */
    }
    return false;
  }

  /**
   * Returns the hashCode for the object.  This must be defined
   * here to ensure 100% pure.
   *
   * @return the hashCode for the object
   */
  public int hashCode() {
    return alignment ^ leader ^ Math.round(position);
  }

  /* This is for debugging; perhaps it should be removed before release */
  public String toString() {
    String buf;
    switch (alignment) {
      default:
      case ALIGN_LEFT:
        buf = "";
        break;
      case ALIGN_RIGHT:
        buf = "right ";
        break;
      case ALIGN_CENTER:
        buf = "center ";
        break;
      case ALIGN_DECIMAL:
        buf = "decimal ";
        break;
      case ALIGN_BAR:
        buf = "bar ";
        break;
    }
    buf = buf + "tab @" + String.valueOf(position);
    if (leader != LEAD_NONE) {
      buf = buf + " (w/leaders)";
    }
    return buf;
  }
}
